232 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Besides the ordinary accessories, the instrument can be supplied 

 with a dust-proof nose-piece, and a swing-out substage for a condenser 

 (figs. 38 and 39). 



Fig. 39. 



Fig. 38. 



Ashe's Two-speed Fine Adjustments.! — A. Ashe's designs are in- 

 tended to produce an adjustment which should combine the slowest and 

 smoothest motion possible with the capability of giving a far more rapid 

 motion when needed. Fig. 40 shows his first arrangement. It consisted 



Fig. 40. 



of a hollow screw of comparatively coarse pitch G, to which the lower 

 milled head B was attached. This worked in the cap C on the top 



* Journ. Quek. Micr. Club, viii. (1901) pp. 131-G (3 figs.).] 



